I think the major difference between the RT and x86 versions of Surface will be price. Of course, the thing isn't on the market yet so it is all rumour.

The speculation I have seen suggests x86 pricing in line with what we see currently with Ultrabooks, so in the $1k ball-park here in NZ. Who know if the US$199 thing is real but with some sort of ongoing subscription for media delivery it may just work. Or it may be a ploy to get people used to Win8 and encourage desktop adoption.

It looks like, and this is me speculating, that the RT version is being pitched at the consumer market. I don't think it is a truly direct iPad competitor because it has a built in keyboard and stand which suggests not so much using it while sitting in an armchair, but of course you can.

The x86 appears, more speculation, to be a pitch at the professional market. Lighter than a laptop but more functional that a traditional tablet. Yes, it will cost more but we are talking about a 'work machine' rather than a 'media consumption device'. So, if you travel a lot for work this could really be the thing.